Hy Ruth. There are many kinds of trading platforms.
Centralized,Dezentralized,or Hybrid are available.
Just search on google by yourself, you can choose which one you prefer.
Each market have their own rules, term , and conditions. You should understand about their rules first, then learn about their features.
But be careful, there are so many scam markets out there.
Just choose which legit ones. Such as binance, kucoin, idex, erherdelta, quoine/qryptos (now rebranding as liquid), etc.